1. Technical Field
This disclosure relates to: a latent electrostatic image bearing member used for a photocopier, a Facsimile, a laser printer and a direct digital plate maker, which is hereinafter referred to also as a photoconductor or an electrophotographic photoconductor; and a process cartridge, an image forming method and an image forming apparatus which uses thereof.
2. Description of the Related Art
Over ten years have passed since a plan of action ‘Agenda 21’ established with hope for handing the rich global environment on to the next generation was adopted, and public awareness towards the environmental conservation has considerably deepened. For example, separation of recyclables from non-recyclables and frequent use of the blank sides of used sheets of paper as printer sheets are examples of immediate change in awareness. Today, the environmental performance of an industrial product has been generally emphasized such that it influences the future of the product. Under such circumstance, the usage pattern of a photoconductor still has a strong aspect as a disposable supply product, and the situation is such that the impact on the global environment cannot be accepted. In response to this, it is required to suppress the abrasion and scratches on a photoconductor in view aspects of design and usage of the photoconductor. At the same time, the damage to the contacting members disposed around the photoconductor should be reduced. Once these are achieved, it becomes possible to suppress the temporal degradation of an image forming engine. As a result, the frequency of component replacement as well as the replacement of the apparatus itself may be reduced, which can contribute to the reduction of environmental burdens such as resource saving and prevention of air pollution.
An amorphous silicone photoconductor is a typical heavy-duty photoconductor today. The production cost of the amorphous silicone photoconductor is high since the manufacturing method thereof is a dry process, and it is used only for high-end apparatuses with some exceptions. The contribution of the high durability of the amorphous silicone conductor to the reduction of environmental burdens is considered insufficient since the use ratio of the amorphous silicone conductor is small. In order to achieve the reduction of environmental burdens, it is desirable that the durability of the photoconductor is enhanced as well as the cost is reduced to increase the usage ratio. To achieve this, it is advantageous to increase the durability of a low-cost organic photoconductor (OPC).
When an abrasion resistance of a metal is given to the organic photoconductor, the abrasion resistance equivalent to the increase in the abrasion resistance is required. When the surface of the photoconductor is scratched, the electrical discharge hazard in an electrophotographic process concentrates in and alters the scratched portions. Also, grooves formed by the scratches are embedded with a toner component or paper powder, and thus, local image deficiencies such as background smear and blur tend to occur. As the abrasion resistance further improves, a scratch once occurred cannot easily disappear with time as if it is engraved. As a result, the scratches inhibit the longer operating life of the photoconductor.
Therefore, an improvement of the operating life of a photoconductor by means of a reduction of the abrasion in the photoconductive layer has been examined, and various proposals thereof have been made. For example, Japanese Patent Application Laid-Open (JP-A) No. 06-118681 proposes the use of a curable silicone resin including colloidal silica as a surface protective layer of a photoconductor.
Also, JP-A Nos. 09-124943 and 09-190004 propose a photoconductor whose surface includes on its surface a resin layer in which an organosilicon modified hole transport compound is bound in a curable organosilicon polymer.
In addition, JP-A 2000-171990 proposes a method for manufacturing a photoconductor in which a curable siloxane resin including a functional group which imparts an electron transport property is cured in a three-dimensional network.
However, these proposals are likely to encounter problems such as reduction of the adhesion to a material and occurrences of a crack due to the use of rigid monomer for enhanced hardness and the increase of the distortion during cure time for enhanced crosslink density. Also, it is extremely difficult to resolve an issue specific to an electrophotography that a scratch is engraved even on a hard surface such as amorphous silicone once a very hard material such as developer carrier is adhered and rubbed on the conductor surface. When a photoconductor having a high surface hardness is used, it is restricted to use a developer carrier having an extremely large particle diameter or to employ a one-component developing method so that the carrier adhesion is avoided. Furthermore, for the improvement of abrasion resistance, it is considered advantageous to improve the stress relaxation rather than to enhance the surface hardness.
So far, no effective solutions have been proposed to improve the durability for scratches of a latent electrostatic image bearing member. Therefore, a latent electrostatic image bearing member is protected with excessive packaging materials so that no scratches are made on the surface of the latent electrostatic image bearing member, and it is currently not given a status as a product which anybody can handle with ease.